Over many decades, storage device manufacturers have been under pressure to increase storage capacity and decrease the size of storage devices. In the disk drive industry, increased recording density has been accompanied by narrowing track pitch density (TPI). However, such TPI narrowing leads to errors caused by magnetic flux leaks.
When data is recorded on a particularly data track of a disk device, magnetic flux leaks from the recording and affects data integrity on adjacent data tracks and far data tracks. When the recorded data has been updated many times, data recorded on adjacent tracks or on far tracks can be corrupted and bit values stored on such tracks may not be recoverable using error recovery techniques, such as error correction codes (ECC). For adjacent tracks, such a phenomenon is known as adjacent track interference (ATI). For far tracks, such a phenomenon is known as far track erasure or far track interference (FTI). Depending on the write head design, both ATI and FTI effects occur during the writing of data tracks.
Such ATI or FTI effects can be influenced by manufacturing tolerances for write heads and magnetic media. In particular, the arcuate movement of a write head and armature and the geometries of the head and media may also alter the impact ATI or FTI has on stored data as the write head moves across the surface of the storage media.
Error correction techniques can be utilized to correct for soft read errors. Soft read errors are those errors that are recoverable by error correction techniques, such as ECC. However, data encoding and ECC are limited in the number of bit errors that can be corrected by hard drive electronics. When there are too many bit errors, data bits may not be recovered and as such the data block is considered unrecoverable. In particular, when the ATI/FTI degradation is too far along in the data block, the data track may be unrecoverable.
As such, an improved method of data storage would be desired.